This application claims the priority of German patent application Serial No. 197 56 958.7 filed Dec. 20, 1987. The disclosure of this German patent application, as well as that of each other patent application and/or patent mentioned in the specification of the present application, is incorporated herein by reference.
The invention relates to improvements in apparatus for applying coats or films of an adhesive to selected sides or surfaces (normally to the spines) of stacks, blocks or piles consisting of or comprising overlying or overlapping sheets, panels and/or plates of paper, cardboard or the like. For the sake of brevity and simplicity, the accumulations of sheet-like commodities will be referred to as stacks, and those selected elongated sides or surfaces of the stacks which are to be provided with films or coats of a suitable adhesive will be referred to as spines. Finished products which are obtained by resorting to the apparatus of the present invention can constitute legal pads or other types of stationery products, portions of books or the like.
It is well known to establish more or less permanent connections between selected edges of overlapping paper sheets or the like by providing such edges with a coat or film of a suitable adhesive. Reference may be had, for example, to published German patent application No. 34 20 875 A1 which discloses an apparatus wherein the means for applying a coat of adhesive to the spine of a stack of paper sheets or the like comprises a series of successive adhesive-applying rollers. Since the rollers must be caused to bear upon the spine of the stack which is located at the coating station, such apparatus cannot invariably ensure the application of an adhesive coat or layer having an optimum width. Moreover, such apparatus cannot apply to a spine an accurately selected quantity of adhesive; this can entail pronounced changes in the thickness and strength of the applied adhesive coat.
An object of the invention is to provide an apparatus which constitutes a pronounced improvement over the apparatus disclosed in the aforementioned published German patent application Serial No. 34 20 875 A1.
Another object of the invention is to provide an apparatus which can provide the spines of a short or long series of successive stacks of paper sheets or the like with adhesive films, layers or coats of optimum width.
A further object of the invention is to provide an apparatus which can ensure a predictable and optimal distribution of adhesive in the longitudinal and/or in the transverse direction of the spine of each of a short or long series of stacks of paper sheets or the like.
An additional object of the invention is to provide the improved apparatus with novel adhesive applying and distributing means.
Still another object of the invention is to provide an apparatus which can apply highly satisfactory coats or films of adhesive to the spines of large numbers of stacks per unit of time.
A further object of the invention is to provide an apparatus which can be readily and accurately adjusted to apply highly satisfactory coats or films of adhesive to relatively wide, relatively narrow, relatively long and/or relatively short spines of stacked paper sheets or the like.
Another object of the invention is to provide an apparatus which can properly treat stacks which consist of or contain relatively soft, relatively, hard, relatively stiff, readily flexible and/or other sheets with the same or at least satisfactory degree of facility and predicability.
An additional object of the invention is to provide a novel and improved conveyor for delivery of successive stacks of a series of stacks to the adhesive applying or coting station.
Still another object of the invention is to provide the above outlined apparatus with novel and improved means for supporting, advancing, adjusting and/or otherwise manipulating the adhesive applying implement or implements.
A further object of the invention is to provide a novel and improved method of applying films or coats of a flowable adhesive substance to the spines of stacked paper sheets or the like in such a way that the applied adhesive is prevented from contacting any and all surfaces other than the spines of the stacks.
Another object of the instant invention is to provide a series of stationery products or analogous products which are obtained or at least partially finished by resorting to the above outlined method and to the above outlined apparatus.
One feature of the present invention resides in the provision of an apparatus for applying coats of a suitable adhesive to selected elongated sides of a series of successive stacks of overlapping sheets at an adhesive applying or coating station. The improved apparatus comprises intermittently operated conveyor means for delivering successive stacks of the series to and for temporarily maintaining the thus delivered stacks at the coating station so that the selected elongated side of the stack at the coating station assumes a predetermined position and orientation, and means for applying a film or layer or coat of adhesive to the selected elongated side of the stack at the coating station. The means for applying comprises at least one adhesive discharging nozzle and means for moving the at least one nozzle longitudinally of and parallel to the entire selected elongated side of the stack at the coating station.
The at least one nozzle is preferably provided with a slot-shaped adhesive discharging orifice having a length which at least approximates the width of the selected elongated side of the stack at the coating station. The orifice extends transversely of such elongated side.
The apparatus preferably further comprises means for shifting the at least one nozzle between an operative position in which the nozzle can discharge adhesive against the selected elongated side of the stack at the coating station and an inoperative position in which the nozzle is spaced apart from the selected elongated side of the stack at the coating station.
Still further, the apparatus preferably comprises means for adjusting the at least one nozzle transversely of the selected elongated side of the stack at the coating station. The means for moving the at least one nozzle can comprise a frame which is movable longitudinally of the selected elongated side of the stack at the coating station, and the aforementioned means for adjusting can comprise a nozzle holder which is shiftable in the frame transversely of the selected elongated side of the stack at the coating station, and means for shifting the nozzle holder.
The conveyor means can comprise pairs of clamping elements which are arranged to engage the stacks adjacent to the respective selected elongated sides. The clamping elements are preferably provided with exposed surfaces which extend longitudinally of the selected elongated sides of the stacks being engaged by the clamping elements, and the moving means of such apparatus can comprise followers arranged to track the exposed surfaces of clamping elements which engage the stack at the coating station. Such moving means preferably further comprises the aforementioned frame which is movable longitudinally of the selected elongated side of the stack at the coating station and has elastic portions which are deformable transversely of the selected elongated side of the stack at the coating station. The followers can be mounted on or in the frame and each such follower is arranged to track the exposed surface of one of the two clamping elements for the stack at the coating station. The followers can include or constitute rollers. The arrangement can be such that one of the followers is rotatable relative to the frame and another follower is movable toward and away from the one follower transversely of the selected elongated side of the stack at the coating station. Still further, the moving means can comprise means (e.g., a fluid-operated or a resilient device) for yieldably urging the other follower toward the one follower.
In accordance with a presently preferred embodiment, the conveyor means comprises a turret indexible about an axis which is at least substantially parallel to the selected elongated side of the stack at the coating station. The turret has a plurality of axially parallel peripheral receptacles for portions of stacks, and each such receptacle includes a pair of clamping elements which engage the stack in the respective receptacle adjacent the selected elongated side of such stack. The axis of the turret is or can be at least substantially horizontal, and the coating station can be disposed at a level below such axis.
As already mentioned hereinbefore, the selected elongated sides can constitute elongated spines of the respective stacks, and the means for applying can comprise a plurality of adhesive discharging nozzles. The means for moving can comprise a carriage which is movable longitudinally of the spine at the coating station in a first direction and in a second direction counter to the first direction. As a rule, or at least in many instances, the nozzles of the aforementioned plurality of nozzles include first and second nozzles which are at least substantial mirror images of each other with reference to a plane extending at right angles to the aforementioned first and second directions and located between the two nozzles.
Each nozzle can have an elongated slot-shaped adhesive discharging orifice of a length at least approximating the width of the spines, and such orifices extend transversely of the spine on the stack at the coating station.
The nozzles are or can be activatable and deactivatable independently of each other to respectively discharge and interrupt the discharging of adhesive. The first nozzle is activated and the second nozzle is deactivated in response to movement of the carriage in the first direction, and the second nozzle is activated and the first nozzle is deactivated in response to movement of the carriage in the second direction.
The just described apparatus preferably further comprises means for shifting the first and second nozzles independently of each other between operative and inoperative positions in which the respective nozzle contacts and is spaced apart from the spine of the stack at the coating station.
The moving means preferably further comprises a discrete frame or support for each of the plurality of nozzles; the frames are supported by and they are shiftable relative to the carriage. Such moving means can further comprise means for shifting each of the frames relative to the carriage between a first and a second position in which the respective nozzle is ready to apply adhesive to and is spaced apart from the spine of the stack at the coating station. The nozzles are or can be adjustable in the respective frames transversely of the spine of the stack at the coating station, and the means for applying can further comprise means for adjusting the nozzles relative to the respective frames. Such adjusting means can comprise a discrete nozzle holder which is shiftably mounted in each of the frames for movement transversely of the spine of the stack at the coating station, and means for shifting the nozzle holders relative to the respective frames.
As already mentioned hereinbefore, the conveyor means can comprise pairs of clamping elements serving to engage the stacks adjacent the respective spines. Such clamping elements are preferably provided with exposed surfaces extending longitudinally of the spines of the stacks being engaged by the clamping elements, and the moving means of such apparatus preferably further comprises followers serving to track the exposed surfaces of clamping elements which engage the stack at the coating station. The aforementioned discrete frames are mounted on and are movable with the carriage and preferably have elastic portions which are deformable transversely of the spine of the stack at the coating station. The followers include pairs of followers carried by the frames, and each follower of each such pair serves to track the exposed surface of a different one of the clamping elements which engage the stack at the coating station.
The followers can include rollers and one roller of each pair is rotatable relative to the respective frame; the other roller of each pair is movable toward and away from the one roller of the respective pair transversely of the spine of the stack at the coating station. The means for applying can further include means for yieldably urging the other roller of each pair toward the one roller of the respective pair.
As already explained hereinbefore, a presently preferred conveyor means comprises a turret which is indexible about an axis that is at least substantially parallel to the spine of the stack at the coating station; the turret has a plurality of axially parallel peripheral receptacles for portions of stacks, and each receptacle includes a pair of clamping elements which engage the stack in the respective receptacle adjacent the spine of such stack. The axis of the turret is or can. be at least substantially horizontal, and the coating station is or can be installed at a level below such axis.